Vulnerability · Published Jul 14, 2026 · Assigned by GitHub_M
CVE-2026-45753Symfony: HtmlSanitizer UrlAttributeSanitizer Omits action/formaction/poster/cite — javascript: URI Survives Sanitization (XSS)
Low 2.1
In plain English
A low-severity cross-site scripting in html-sanitizer from symfony. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 27% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
Symfony is a PHP framework for web and console applications and a set of reusable PHP components. From 6.1.0-BETA1 until 6.4.40, 7.4.12, and 8.0.12, UrlAttributeSanitizer::getSupportedAttributes() omits URL-valued attributes including action, formaction, poster, and cite, so configurations that admit those attributes can leave javascript: URIs unsanitized and enable XSS when the resulting HTML is rendered or a victim submits a form or clicks a button. This issue is fixed in versions 6.4.40, 7.4.12, and 8.0.12.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:13 | symfony | 6.4.41+dfsg-0+deb13u1 | DEBIAN-CVE-2026-45753 |
| Debian:14 | symfony | 7.4.12+dfsg-1 | DEBIAN-CVE-2026-45753 |
| Packagist | symfony/html-sanitizer | 6.4.40 | GHSA-hhg7-c65m-h7ff |
| Packagist | symfony/html-sanitizer | 7.4.12 | GHSA-hhg7-c65m-h7ff |
| Packagist | symfony/html-sanitizer | 8.0.12 | GHSA-hhg7-c65m-h7ff |
| Packagist | symfony/symfony | 8.0.12 | GHSA-hhg7-c65m-h7ff |
| Packagist | symfony/symfony | 6.4.40 | GHSA-hhg7-c65m-h7ff |
| Packagist | symfony/symfony | 7.4.12 | GHSA-hhg7-c65m-h7ff |
| Ubuntu:25.10 | symfony | no fix listed | UBUNTU-CVE-2026-45753 |
| Ubuntu:26.04:LTS | symfony | no fix listed | UBUNTU-CVE-2026-45753 |
| Ubuntu:26.10 | symfony | no fix listed | UBUNTU-CVE-2026-45753 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| symfony | symfony | >= 6.1.0-BETA1, < 6.4.40>= 7.0.0-BETA1, < 7.4.12>= 8.0.0-BETA1, < 8.0.12 |
| symfony | html-sanitizer | >= 6.1.0-BETA1, < 6.4.40>= 7.0.0-BETA1, < 7.4.12>= 8.0.0-BETA1, < 8.0.12 |
Weakness: CWE-79, CWE-184 · Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
References
- https://github.com/symfony/symfony/security/advisories/GHSA-hhg7-c65m-h7ff x_refsource_CONFIRM
- https://github.com/symfony/symfony/commit/487728e7e180a674a6d4c01bd0cb56161cc441b7 x_refsource_MISC
- https://github.com/symfony/symfony/releases/tag/v6.4.40 x_refsource_MISC
- https://github.com/symfony/symfony/releases/tag/v7.4.12 x_refsource_MISC
- https://github.com/symfony/symfony/releases/tag/v8.0.12 x_refsource_MISC